The present invention relates to an oral silybin composition having improved silybin bioavailability and more particularly, to a micro-emulsion composition comprising a Carduus marianus extract or silybin.
Silybin, the primary component of a Carduus marianus extract, is known to have excellent activity in protecting liver cells from harmful effects caused by smoking, drinking, overworking, environmental contaminants, stress or liver-damaging drugs. However, the bioavailability of orally administered silybin is very low due to its low solubility in water.
Korean Patent Publication No. 96-13361 teaches a method for increasing the solubility of silybin by dissolving silybin in a mixture of polyethylene glycol and ethanol, and adding the resulting solution to an aqueous polysorbate solution to formulate a silybin solution. However, this method has the problem that the incremental increase in the silybin solubility is only marginal, requiring the use of a large amount of the aqueous solution.
Korean Patent Publication No. 96-777 discloses a silybin complex preparation using a mono- or disaccharide, a cellulose derivative or 1-vinyl-2-pyrrolidone as an excipient and having 2-fold higher silybin bioavailability as compared with conventional formulations. This preparation is commercially available from Bugwang Medicine under the trade name of Legaron(copyright) 140 capsule. However, the manufacturing process of the above preparation is very complicated and the in vivo bioavailability of silybin achievable is still limited.
Accordingly, there has existed a need to develop an oral silybin composition having improved in vivo bioavailability of silybin.
It is, therefore, an object of the present invention to provide an improved oral composition of silybin.
In accordance with one aspect of the present invention, there is provided a micro-emulsion composition for oral administration comprising a Carduus marianus extract, silybin or a silybin derivative; an organic solvent as co-surfactant; a surfactant; and an oil.